Final answer:
The user should contact the help line of the cable company for further help with the Internet connectivity issue.
Step-by-step explanation:
If a user's home computer is working properly but they cannot access the Internet, they should contact the help line of the cable company for further assistance. The cable company is responsible for providing the Internet connection, so they should be able to help troubleshoot and resolve the issue. The operating system vendor, computer manufacturer, and support web site of the computer vendor may not have the expertise or authority to address a connectivity problem caused by the cable company.